So I am helping a friend build a small ish grow box, it will be 2x2x4 and it is possible to get fresh air in there, just a bit of a struggle since they want to put it in a closet, and so I read about one of these in a magazine a while back and not exactly sure what they do, It says they help control smell but would you still need fresh air? http://www.htgsupply.com/Product-Ozone-400.asp That would be the exact one I buy.
no im pretty sure it reduces smell and can possibly damage your health you will need extracion so ya plant get co2(ozone is O3) and cools off